This invention relates to aqueous automatic dishwashing detergent compositions which have a yield value and are shear-thinning. Compositions of this general type are known and disclosed in U.S. Pat. No. 4,116,851 to Rupe et al, issued Sept. 26, 1978; U.S. Pat. No. 4,431,559 to Ulrich, issued Feb. 14, 1984; U.S. Pat. No. 4,511,487 to Pruhs et al, issued Apr. 16, 1985; U.S. Pat. No. 4,512,908 to Heile, issued Apr. 23, 1985; Canadian Patent 1,031,229, Bush et al; European Patent Application 0130678, Heile, published Jan. 9, 1985; European Patent Application 0176163, Robinson, published Apr. 2, 1986; UK Patent Application 2,116,199A, Julemont et al, published Sept. 21, 1983; UK Patent Application 2,140,450A, Julemont et al, published Nov. 29, 1984; UK Patent Application 2,163,447A, Colarusso, published Feb. 6, 1986; UK Patent Application 2,164,350A, Lai et al, published Mar. 19, 1986; U.K. Patent Application 2,176,495A, Drapler et al, published Dec. 31, 1986; and U.K. Patent Application 2,185,037A, Dixit, published July 8, 1987.
U.S. Pat. No. 2,892,797, Alexander et al, issued June 30, 1959, teaches a process for modifying a silica sol to provide increased stability. This process comprises treatment with a metalate (e.g., sodium aluminate) solution. U.S. Pat. No. 3,255,117, Knapp et al, issued June 7, 1966, discloses automatic dishwashing detergent compositions in granular form containing an amphoteric metal compound, e.g., an aluminate. Similar disclosures are made in U.S. Pat. No. 3,350,318, Green, issued Oct. 31, 1967; U.S. Pat. No. 3,852,209, Hofmann, issued Dec. 3, 1974; U.S. Pat. No. 3,826,748, Finck, issued July 30, 1974; U.S. Pat. No. 2,575,576, Bacon et al, issued Nov. 20, 1951; U.S. Pat. No. 2,514,304, Bacon et al, issued July 4, 1950; U.S. Pat. No. 2,241,984, Cooper, issued May 13, 1941.
U.S. Pat. No. 3,755,180, Austin, issued Aug. 28, 1973, discloses a composition for use in an automatic dishwasher containing a precipitated silico-aluminate compound. (See also U.S. Pat. No. 3,966,627, Gray, issued June 29, 1976).
Sales literature for polyacrylates and Carbopol.RTM. resins by B. F. Goodrich discloses that using metal ions in combination with polyacrylate polymers can have a dilatory effect.
It has now been found that a polyacrylate thickening system in a liquid automatic dishwashing detergent composition can be enhanced by combining it with an alkali metal silica colloid having dispersed therein an alkali metal aluminate.